You'll have better luck polishing if you use corn cob. You can get larger ground cob at pet supply stores. It will work better for post-load polishing, but it will get stuck in empty bottleneck cases. Mineral spirits tends to slightly soften the corn cob media, making it less abrasive. Treated cob for the right amount of time
will produce a blinding shine if that's what you want. finished_brass.jpeg